clicks with spdif audio recording

I think the problem is not the buffer size, althoug changing the that size the clicks occur in different way. I told you I have no problems with smallest sizes at high freqs (up to 192khz) and more than 15 audio instruments. No clicks anywhere, only when recording from digital input. Those clicks are not the common spaced clics (1 per second or so), but there are many of them, as a low freq. noise. I gave that info supposing to help about where is the problem, but I know this (buffer size) is not the problem. Thanks anyway for your reply.
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Hi again, and thanks again. The same configuration with optical cables works fine (obviously with other devices, as if my spdif device had optical output i'd already used it). From smallest to largest buffer sizes. My spdif cables are good quality and short ones. I suspect there is something wrong in my clock/synch settings, but I don't know enough about it. I've told you that "clicks" are not the eventual clicks produced by not enough time to process the audio data. That clicks are very regular and may be 50 per second (I insist: not the 1 or 2 per second when you have very low latency settings). Are not the buffer size, I agree the problem is something related to sync, and the fact the clicks sound different at different buffer sizes simply provides information about something is happening each time a buffer is loaded/released. I thing there's one click each time a buffer is used. E.g. buffer size 2048 at 48khz produces 23 clicks per second, buffer size 32 samples produces 1500 clicks (you hear like a noise). I'm going to count those clicks, but i'm sure is that way.


Hope i'm not too boring and someone can give me the solution. Those who had tha same problem or those who worked correctly with spdif inputs. Thanks again.

Hi John and Alexitoo,

I've read over your comments but not with too detail as I think my "problem" is solved. Let's go what I did:

All i have to do is to follow this steps in this strict sort:
1-switch on my digital output device (in my case a synth-keyboard)
2-set the audio card control panel sync to external-coaxial
3-open LP8!!

I don't remember what i was doing before, but i'm not sure the steps were followed that way. I think I opened first LP8 and later was set my audio card clock to external => don't think logic can manage this change of audio sync.

As doing this everything is working fine, i haven't made a look at logic prefs (external sync, audio bitrate, etc), but i think audio card sync is no relevant to logic to work. (And i think by chance i have 48kHz as default bitrate, that is the same for my spdif device. If wasn't it the only thing i should set in logic would be the audio bit rate). That's all. Dont' completely understand but IT WORKS!

Thanks also for your comments and hope my final solution will be useful for you.

saludos alexitooo

ramon

ok, i haven't read completely your posts, sorry, i'll do. in my scenario i need to record from an external device (in my case the sound of a kurzweil contoller, which have a digital 48kHz 24bit digital output). I need to tell my soundcard who have the master sync clock. You must do that everytime you record into your computer from an external digital device (doesn't matter coaxial or optical). In my case, i set my audio card clock sync to external (and coaxial).
Automatially it detects the 48kHz signal and my OS audio/midi devices panel is showing the 48kHz bitrate. Then I open logic and I can record without noise nor clicks. What i've just seen is that if you have (in project audio settings) a different bitrate (e.g. 44100), once you've recorded from the digital (or analog, whatever you want), a conversion to the project settings is done. So if you want to record from your digital external device you must set the according project audio bitrate to the external bitrate detected. Hope to have been clear about what is my scenario and hope it can be useful.

saludos!